Figure 1.

CNTF is repressed by ECM and specific αvβ5 integrin and neuronal Thy-1 ligand. A) C6 astroglioma cells grown for 4 h on laminin (LAM), fibronectin (FN1) and vitronectin (VTN) had lower levels of CNTF mRNA compared to poly-d-lysine control (Ctrl, set at 1.00) as quantified by qRT-PCR. Fibrinogen (FG), thrombospondin (TSP), and collagen (COL) had no significant effect. Because of the binding specificity this suggests that a limited number of integrins repress CNTF. B) Neutralizing antibodies against αv or β5, but not α6 or β1 induce CNTF mRNA expression relative to IgG (Ctrl) in C6 cells after 4 hours. Antibody selection was guided by elimination of unlikely candidates (Table 1). The β5 subunit is only found in αvβ5. C) Neutralizing antibody against Thy-1, an αvβ5 ligand, induces CNTF mRNA expression in primary astrocyte-neuron co-cultures compared to IgG (Ctrl). Data represent means (± SEM) of 3–4 (A) or 6 (B, C) independent experiments and are fold changes expressed relative to controls.